1. Field of the Invention
The present invention relates to a method and an apparatus for data processing, and more particularly, to a method and an apparatus for processing data including compressed data and non-compressed data.
2. Description of the Background Art
In general, in a computer system, the data compression is utilized at a time of transferring or storing data for the purpose of shortening a transfer time or saving a memory medium. Compressed data usually form a sequence different from original data, and can be restored into totally or almost equivalent form as the original data by an expansion which is an inverse conversion of the compression.
Conventionally, the entire data to be transferred or stored are compressed in order to take a full advantage of the effect achieved by the compression. Here, there are cases in which the entire data are compressed collectively, as well as cases in which the compression is carried out in units of a plurality of fixed length blocks.
However, in a case of compressing the entire data collectively, a considerable time is required for restoring the original data by expanding the compressed data. In particular, under the interactive data utilization environment in which a user interactively selects data to be referred on a display screen, which data is going to be referred when is not known in advance, so that the expansion processing can be applied only after a desired data is requested by a user. Consequently, whenever a user requests to refer to a data, a user is going to be kept awaiting for a considerable amount of time.
Also, in a computer system for which a battery power consumption can potentially be a problem as in a case of a portable information device, the battery power can be largely consumed by a time required for the expansion processing, and this fact can make it difficult to use such a computer system over an extended period of time.
Thus, conventionally, the compression for the purpose of reducing an amount of data can shorten a transfer time or save a memory medium, but a considerable amount of time is required for restoring data in usable form because the expansion is necessary at a time of referring to data, and a considerable battery power consumption is required for referring to data many times in a portable information processing device.